University:
York University
Course:
CHEM 1001 | Chemical Dynamics
Academic year:

2022
Views:

333

Pages:

3
Author:

Niklas

Chapter 8: Common Ion Effect and Buffer Solutions Buffers: Solutions that contain a weak acid and its conjugate base (both in significant amounts). Buffer Resistance: Buffers resist changes in pH and are most effective when pH is close to pKa. Buffers in Blood: Blood pH ranges from 7.34-7.45 (ΔpH: 0.06). Variations of 0.2 are very bad. 5 Different Buffer Systems in Blood: H₂CO₃/HCO₃⁻, H₃PO₄/H₂PO₄⁻, H₂PO₄⁻/HPO₄²⁻, H₂CO₃/H₂O, CH₃COOH/CH₃COO⁻. Respiratory Pathway: CO₂ + H₂O ↔ H₂CO₃ ↔ HCO₃⁻ + H⁺ (in blood) (in lungs) Solving Buffer Solutions: Use final molar ratios in the pH = pKa + log([A⁻]/[HA]) equation. Diprotic Acids: Have two steps. Buffer Capacity: The amount of acid or base that can be added without running out of HA or A⁻. Calculation: Only need to know concentrations (molar amounts) to calculate buffer pH. 03/04/2022 Chapter 8 •Titrations an analytical method that exploits our ability to measure volumes accurately (4-5 sig liga) acid-base reactions redox reactions precipitation reactions 1:1 or 1:2 molar ratio -unknown in beaker compared against standardized stang base which is calibented against a standard Acid-base titrations Strong acid-strong base titration Titration Problem (find and plt) -calculate moles reacted -divide the moles by the total volume (including volume acided) •Center of buffer region in titration is the crossing paint of distribution curves -independent of solution concandration Equivalence point is where. HA is completely converted to weak base If the pll is close to seven, you don't need to take H₂O into account unless small concentration Acid-Base Indicator -most indicators are work acids where its acid form of conjugate base have different colors